{85a} We have the testimony of two of the labourers employed in the shaft (Cheeseman and Belton) who agree in giving this depth. They also state that the particular stratum was 54ft. thick; that the set of the current was from south-east to north-west, running from a crack in one side of the shaft into a corresponding crack in the opposite side, and that they both assisted in making a brick and cement lining to the shaft, leaving a channel behind for the water to run round half the circumference, from crack to crack. {85b} We may further add that it is at the junction of the Northampton sand with the underlying lias, that we find numerous springs in other parts of the county; as at Navanby, Waddington, Lincoln, Blyborough, Kirton, and several other places. The Government “Geological Survey Memoir” for the country around Lincoln (p. 208) agrees in saying that the Woodhall water comes from the “inferior oolite” which comprises the Northampton sands. {87a} “Life of Nansen, 1881–1893,” by W. C. Brögger and Nordahl Rolfsen. (Longmans, 1896, pp. 350–357). {87b} Ibidem, p. 139. {88a} Ibidem, p. 123. {88b} This subject has been fully gone into by Mr. P. F. Kendall, F.G.S., in his article “The Cause of an Ice-age,” contributed to the “Transactions of the Leeds Geological Association,” part viii. Other ice-streams also passed down various alleys from Teesdale to Airedale, and the Ouse. {88c} See an article “On the Occurrence of Shap Granite Boulders in Lincolnshire,” by Mr. W. T. Sheppard, in the “Naturalist” of 1896, pp. 333–339. Also the “Presidential Address to the Yorkshire Naturalists’ Union,” by J. Cordeaux, F.R.G.S., M.B.O.U., in the “Naturalist” for 1897, pp. 195, 6. See also a very interesting article in the “Fortnightly Review,” November, 1863, on “The Ice-age and its Work,” by A. R. Wallace, F.R.S. {89a} Mr. J. Cordeaux gives this thickness in the “Naturalist” (1897, p. 186). Professor J. Geikie says it “did not exceed 3,500ft. or 4,000ft. at most, and would take 3,000ft. as an average.” (“The Glacial Period and Earth Movement,” a paper read before the Victoria Institute in 1893. Trans. No. 104, pp. 221–249, where also the question is largely considered of the causes of the Ice-age). {89b} Mr. Wallace says; “Every mountain group, north of the Bristol channel, was a centre from which, in the Ice-age, glaciers radiated; these became confluent, extensive ice-sheets, which overflowed into the Atlantic on the west, and spread far over the English lowlands on the east and south.” “The Ice-age and its work.”—“Fortnightly Review,” Nov., 1893, p., 269. {90} Quoted by Mr. Wallace in “The Fortnightly,” p. 630. {91a} Quoted from “Glacialist’s Magazine,” “Fortnightly Review,” Nov., 1893, p. 631.